Variable magnification optical system and imaging apparatus

A variable magnification optical system comprising:

• a first lens group having negative refractive power;
• a stop;
• and
• a second lens group having positive refractive power, which are arranged from the object side of the variable magnification optical system in the order mentioned above,
• wherein the magnification of the variable magnification optical system is changed by changing a distance between the first lens group and the second lens group in the direction of an optical axis, and
• wherein the first lens group includes a plastic lens having negative refractive power, and
• wherein the second lens group includes a plastic lens having positive refractive power, and
• wherein the following formulas (1) and (2) are satisfied:
• 5.0<fpp/fw<7.5 (1);
• and
• −7.0<fpn/fw<−6.0 (2), where
• fpn is the focal length of the plastic lens having negative refractive power,
• fpp is the focal length of the plastic lens having positive refractive power, and
• fw is the focal length of the entire system of the variable magnification optical system at a wide angle end.